White smoke from exhaust. Other colored exhaust smoke, what do they mean?
In conventional automobiles or even hybrids, exhaust smoke is to be expected. These smokes generally go unnoticed in modern vehicles because our engines are efficient and our catalytic converters are great.
The problem arises when you start to notice your exhaust smoke. Not your winter thin white smoke that happens due to evaporation. But dense coloured exhaust smoke can easily be identified as “Not Normal”.
A prime example is the extremely dense and dark exhaust smoke produced by old diesel vehicles. Despite their big engines, the level of pollutants coming from the exhaust is not normal.
So, What are these coloured exhaust smokes? What different coloured exhaust smoke is there? And What do they mean?
Different Coloured Exhaust smokes and their Causes:
There are four different coloured exhaust smokes other than your normal. You have White, Black, Grey and Blue. Each coloured smoke is caused due to unique issues happening inside your engine. Unfortunately, any of this exhaust smoke means serious problems to the engine that needs to be taken care of immediately.
White Coloured Exhaust Smoke:
Unlike normal white smoke in winter, White coloured exhaust smoke is dense exhaust smoke that is milky white. It will come out of your vehicle continuously like a popped smoke grenade. Along with the white smoke, you might also face issues with engine overheating and low coolant levels.
Cause:
That is because the main cause of White Colored smoke is burning coolant. Somehow, the coolant in your car is getting into the engine and getting burnt which is causing white smoke. And while coolant leak happens due to many reasons, coolant leaking inside the engine happens due to a blown head gasket, cracked cylinder block or damaged cylinder heads.
Cost:
Whatever the cause might be it is an expensive fix. A blown head gasket alone costs $1000 and a damaged cylinder head goes around the same. However, problems with Cracked cylinder blocks mean a bill above $3000 - $4000.
Black Coloured Exhaust Smoke:
Black-coloured smoke is the most common type of coloured exhaust smoke seen in vehicles. The denser darker colour simply represents the heavy amount of pollutants present in it. These types of smoke are very harmful to humans due to the high concentration of carbon.
Cause:
The heavy presence of carbon in these smoke is generally due to three reasons:
- The engine has gone old and has developed high carbon deposits inside it.
- The engine is not able to efficiently burn the fuel. It can be burning too much fuel or has less air supply to burn it. For this, error codes like P0172/P0175 System too rich can also be raised.
- You have a failed catalytic converter which cannot filter the exhaust smoke. As a result, your exhaust is smoking unfiltered burnt fuel that is carbon monoxide.
Cost:
When faced with carbon deposits, the fixing can be as simple and cheap as using an engine flush running under $100. Or expensive and complex as getting it thoroughly cleaned, charges for which run around $400-$600.
With problems like an engine running too rich or burning too much fuel, the issue is generally with a clogged air filter or bad fuel pump. Replacing a clogged air filter is an easy process that runs around $80. But a bad fuel pump is an easy $200.
As for the failed catalytic converter, repairs go around $1000 while replacement runs above $2000.
Blue/Grey Coloured Exhaust Smoke:
Blue and Grey Coloured smokes are generally caused due to common reasons. Often it is hard to differentiate between them. What you can be sure about though is none of them is good news. These smokes similar to white smoke are caused due to leaks in the engine.
Cause:
Other than the coolant leak, fluid-like transmission fluid and engine oil can also get burnt inside the engine. These cause blue or grey smoke.
Oil leaking to the engine can be due to a bad turbocharger, worn-out piston rings, blown head gaskets or a leaking seal. A failing PCV valve can also build pressure inside the crankcase opening oil past seals and causing leaks to the engine.
Transmission fluid from your automatic can also be leaked inside the engine because of a faulty vacuum modulator. All of which is the culprit behind blue or grey exhaust smoke.
Cost:
Oil leaks inside the engine can happen due to many ways, each of which has specific repair cost and complexity. A blown head gasket causing an oil leak needs replacement, which is a complex process, hence expensive around $1000. A bad PCV valve on another hand doesn’t cost more than $100.
For a leaking turbocharger, the issue can be a faulty oil line that runs around $400-$500 replacement. Oil leak in the engine due to worn out pistons however needs piston ring replacement which depending on your car can be between $1500-$4500. Depending on the damage, transmission fluid leak repairs also run between $100-$1000.
Is it necessary to fix coloured exhaust smoke?
Repairs when having different coloured smokes can be expensive. But avoiding such repairs, would only further damage your engine, eventually leading to overheating and engine seizing.
It is recommended that you take care of the issue as soon as possible. There are scenarios where you might face two different coloured exhaust smokes at once. Like having both coolant and oil burning inside the engine. A blown head gasket can cause both, can result in overheating, seizing and eventually engine meltdown.
What initially was $1000 could now cost you more than $5000. This is why it is necessary to fix the coloured exhaust smoke problem.